Syringe infusion pumps, relatively recent inventions, are devices into which a dosage syringe is positioned with the downstream end in an intravenous line connected to a patient and the plunger end against a user programmed drive mechanism. An example of this invention is described in U.S. Pat. No. 4,804,368 (Skakoon) The particular user software program determines the rate of drug injection into the intravenous line.
Syringe infusion pumps have contributed several outstanding advances to the field of medicine. First, medical personnel may be utilized in other important areas at a time when manpower is becoming more of a critical factor.
A second advantage of this infusion pump is that with proper programming, banks of hypodermic syringes containing different dosages and types of drugs being injected into intravenous lines to different patients, may all be controlled from one machine.
The prime technical problem facing Biomedical and Clinical personnel is that infusion pumps must be extremely safe and reliable or the life of the patient is at stake. This level of confidence is mandatory.
Consequently, possible malfunctions have to be addressed in the infusion pump equipment. Possible problems include, but are not limited to, jamming of the plunger within the syringe, possible air bubbles in the line, false starting of the syringe (siphoning), delivery continued beyond the amount of intended dosage and improper delivery rate. Some of these problems have been resolved by the use of alarms and other fail safe mechanisms at certain points in the syringe cycle. See U.S. Pat. No. 4,854,324 (Hirschmam).
However, for patient safety the common practice has been to return the infusion pumps to the manufacturer for verification of the dosages, delivery rates and alarm systems. This procedure is very time-consuming, very expensive, and necessitates a greater number of infusion pumps. Due to the aforementioned facts, many pumps are not verified on a regular basis.
There are several functions of an infusion pump that must be tested to confirm safety and reliability. It is important to note that the rate of delivery is generally in the range of 0.1 mil/hour to 20 mil/hour. Analyzing infusion pumps necessarily includes flow rate determination, culmulative volume determination, individual dosage volume determination, quantity of fluid remaining in the syringe, occlusion pressure, near end of syringe alarms and end of syringe check. Several devices are on the market that provide testing of some, but not all of the above parameters of the infusion pump in situ.
In general, the available testing equipment can only check the rate of fluid flow by pumping a standard fluid (water) through the infusion pumps and then by gravometric or volumetric means determine what the flow rate is against time. Difficulties that exist with these devices are that: the infusion pump analysers must be cleaned, and air bubbles have to be eliminated from the tubings and fittings; maintenance and tubing standardization requirements are difficult to substantiate. The rate of evaporation has to be considered during very slow rates. Also, the delivery rate must be non-pulsing in order to set an accurate reading, and these devices can only measure rates down to 0.5 mils/hour. Finally, the present testing devices are unable to measure occlusion pressure, the amount of liquid left in the syringe, the volume, and can only test one or two infusion pumps simultaneously.
There is then a need for a testing device or method which does not utilize fluids, that tracks the manufacturers method of testing their pumps, that can test the entire range of actual dosage, that can be simply calibrated and connected to the pump, that can quickly test all infusion pumps being used in one software program at the same time, that can test both pulsing and continuous flow pumps, and that is relatively inexpensive to make and use in the field.